"We think HP machines are vulnerable. We think they're slow," said Ellison. "We're going to go after them in the marketplace with better software, better hardware and better people, and we're going to win market share."

In a statement to the WSJ, HP dismissed Ellison's claims and declared that disgruntled Sun customers are flocking to the vendor in their droves.

It stated: "Larry Ellison bought a money-losing business that had steady market share declines for years, and which still ranks at the bottom of the market.

"Sun customers are running to HP in droves because they recognise we deliver superior technology, performance and pricing."

Until earlier this year, Oracle and HP had enjoyed a close a technology alliance.

However, in recent months, relations appear to have cooled, with Ellison repeatedly hitting out at his one-time partner for its handling of HP chief executive Mark Hurd's departure.

Microsoft has made an early version of Windows 10 - its next operating system - available for download. The OS promises better integration and harmonisation across platforms, including mobile and desktop.
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